How to get a more detailed information on an object (a list of fields and methods) using Python's pdb?
https://stackoverflow.com/questions/9979467
-
28-05-2021 - |
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I am using pdb (actually ipdb) to debug my Django models.py. In particular I am trying to debug these lines of code:
def add_can_view( sender, **kwargs ) :
#import ipdb; ipdb.set_trace()
for content_type in ContentType.objects.all():
Permission.objects.create(
content_type = content_type,
codename = 'view_{}'.format( content_type.model ),
name = 'Can view {}'.format( content_type.name )
)
post_syncdb.connect( add_can_view )
The code above, which was provided in this question, has an IntegrityError error when I run python manage.py syncdb:
ERROR: An unexpected error occurred while tokenizing input
The following traceback may be corrupted or invalid
The error message is: ('EOF in multi-line statement', (11, 0))
---------------------------------------------------------------------------
IntegrityError Traceback (most recent call last)
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/IPython/utils/py3compat.pyc in execfile(fname, *where)
173 else:
174 filename = fname
--> 175 __builtin__.execfile(filename, *where)
/Users/hobbes3/Sites/mysite/manage.py in <module>()
8 from django.core.management import execute_from_command_line
9
---> 10 execute_from_command_line(sys.argv)
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/__init__.pyc in execute_from_command_line(argv)
441 """
442 utility = ManagementUtility(argv)
--> 443 utility.execute()
444
445 def execute_manager(settings_mod, argv=None):
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/__init__.pyc in execute(self)
380 sys.stdout.write(self.main_help_text() + '\n')
381 else:
--> 382 self.fetch_command(subcommand).run_from_argv(self.argv)
383
384 def setup_environ(settings_mod, original_settings_path=None):
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/base.pyc in run_from_argv(self, argv)
194 options, args = parser.parse_args(argv[2:])
195 handle_default_options(options)
--> 196 self.execute(*args, **options.__dict__)
197
198 def execute(self, *args, **options):
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/base.pyc in execute(self, *args, **options)
230 if self.requires_model_validation:
231 self.validate()
--> 232 output = self.handle(*args, **options)
233 if output:
234 if self.output_transaction:
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/base.pyc in handle(self, *args, **options)
369 if args:
370 raise CommandError("Command doesn't accept any arguments")
--> 371 return self.handle_noargs(**options)
372
373 def handle_noargs(self, **options):
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/South-0.7.4-py2.7.egg/south/management/commands/syncdb.pyc in handle_noargs(self, migrate_all, **options)
88
89 # OK, run the actual syncdb
---> 90 syncdb.Command().execute(**options)
91
92 settings.INSTALLED_APPS = old_installed
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/base.pyc in execute(self, *args, **options)
230 if self.requires_model_validation:
231 self.validate()
--> 232 output = self.handle(*args, **options)
233 if output:
234 if self.output_transaction:
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/base.pyc in handle(self, *args, **options)
369 if args:
370 raise CommandError("Command doesn't accept any arguments")
--> 371 return self.handle_noargs(**options)
372
373 def handle_noargs(self, **options):
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/commands/syncdb.pyc in handle_noargs(self, **options)
108 # Send the post_syncdb signal, so individual apps can do whatever they need
109 # to do at this point.
--> 110 emit_post_sync_signal(created_models, verbosity, interactive, db)
111
112 # The connection may have been closed by a syncdb handler.
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/core/management/sql.pyc in emit_post_sync_signal(created_models, verbosity, interactive, db)
187 models.signals.post_syncdb.send(sender=app, app=app,
188 created_models=created_models, verbosity=verbosity,
--> 189 interactive=interactive, db=db)
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/dispatch/dispatcher.pyc in send(self, sender, **named)
170
171 for receiver in self._live_receivers(_make_id(sender)):
--> 172 response = receiver(signal=self, sender=sender, **named)
173 responses.append((receiver, response))
174 return responses
/Users/hobbes3/Sites/mysite/doors/signals.py in add_can_view(sender, **kwargs)
8 content_type = content_type,
9 codename = 'view_{}'.format( content_type.model ),
---> 10 name = 'Can view {}'.format( content_type.name )
11 )
12
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/models/manager.pyc in create(self, **kwargs)
135
136 def create(self, **kwargs):
--> 137 return self.get_query_set().create(**kwargs)
138
139 def bulk_create(self, *args, **kwargs):
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/models/query.pyc in create(self, **kwargs)
375 obj = self.model(**kwargs)
376 self._for_write = True
--> 377 obj.save(force_insert=True, using=self.db)
378 return obj
379
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/models/base.pyc in save(self, force_insert, force_update, using)
461 if force_insert and force_update:
462 raise ValueError("Cannot force both insert and updating in model saving.")
--> 463 self.save_base(using=using, force_insert=force_insert, force_update=force_update)
464
465 save.alters_data = True
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/models/base.pyc in save_base(self, raw, cls, origin, force_insert, force_update, using)
549
550 update_pk = bool(meta.has_auto_field and not pk_set)
--> 551 result = manager._insert([self], fields=fields, return_id=update_pk, using=using, raw=raw)
552
553 if update_pk:
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/models/manager.pyc in _insert(self, objs, fields, **kwargs)
201
202 def _insert(self, objs, fields, **kwargs):
--> 203 return insert_query(self.model, objs, fields, **kwargs)
204
205 def _update(self, values, **kwargs):
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/models/query.pyc in insert_query(model, objs, fields, return_id, raw, using)
1574 query = sql.InsertQuery(model)
1575 query.insert_values(fields, objs, raw=raw)
-> 1576 return query.get_compiler(using=using).execute_sql(return_id)
1577
1578
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/models/sql/compiler.pyc in execute_sql(self, return_id)
908 cursor = self.connection.cursor()
909 for sql, params in self.as_sql():
--> 910 cursor.execute(sql, params)
911 if not (return_id and cursor):
912 return
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/backends/util.pyc in execute(self, sql, params)
38 start = time()
39 try:
---> 40 return self.cursor.execute(sql, params)
41 finally:
42 stop = time()
/Users/hobbes3/.virtualenvs/doors/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.pyc in execute(self, query, args)
50 def execute(self, query, args=None):
51 try:
---> 52 return self.cursor.execute(query, args)
53 except Database.IntegrityError, e:
54 raise utils.IntegrityError, utils.IntegrityError(*tuple(e)), sys.exc_info()[2]
IntegrityError: duplicate key value violates unique constraint "auth_permission_content_type_id_codename_key"
DETAIL: Key (content_type_id, codename)=(2, view_group) already exists.
I have a feeling that somehow there is a duplicate content_type and the error occurs when I try to apply the permission twice to content_type_id 2, which is auth.group. So when after I uncomment the import ipdb line, I want to check out some objects such as content_type, but if I type that, then all I get is <ContentType: content type>.
I know I can simply go look at the documentation to see the model, but how would you get a list of fields and methods without knowing what the class is?
Also bonus points for solving this error lol.
Soluzione
Use dir (e.g. dir(content_type)) to get a list of attributes (including methods).
In relation to django models, there is also a lot of information inside the _meta property. Explore that with dir(my_model_object._meta).
Altri suggerimenti
Since you're using ipdb (and not pdb), a faster alternative to dir is using the built-in tab completion:
ipdb> foo=""
ipdb> foo. #press tab after writing the dot
foo.capitalize foo.islower foo.rpartition
foo.center foo.isspace foo.rsplit
foo.count foo.istitle foo.rstrip
foo.decode foo.isupper foo.split
foo.encode foo.join foo.splitlines
foo.endswith foo.ljust foo.startswith
foo.expandtabs foo.lower foo.strip
foo.find foo.lstrip foo.swapcase
foo.format foo.partition foo.title
foo.index foo.replace foo.translate
foo.isalnum foo.rfind foo.upper
foo.isalpha foo.rindex foo.zfill
foo.isdigit foo.rjusthere
In case you don't know about it, you can also use tab completion to complete variable names
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